Algorand Application Call Monitor

This example monitors calls to a specific Algorand application and alerts when certain conditions are met.

Setup

1. Get Algorand node URLs:

   • Algod URL: Usually https://mainnet-api.algonode.cloud (public) or your own node
   • Indexer URL: Usually https://mainnet-idx.algonode.cloud (public) or your own indexer

2. Get a Slack webhook (optional): Create a Slack app and add an incoming webhook.

3. Set environment variables:

export ALGOD_URL="https://mainnet-api.algonode.cloud"
export ALGO_INDEXER_URL="https://mainnet-idx.algonode.cloud"
export SLACK_WEBHOOK_URL="https://hooks.slack.com/services/YOUR/WEBHOOK/URL"
export ALLOWED_SENDERS="ADDRESS1,ADDRESS2"  # optional: filter by sender

4. Update the app ID in config.yaml to the application you want to monitor.

5. Run:

watch-tower validate -c config.yaml
watch-tower run -c config.yaml --once

What it does

• Monitors calls to a specific Algorand application
• Filters by sender addresses (if ALLOWED_SENDERS is set)
• Sends alerts to Slack
• Deduplicates alerts for 24 hours

Customization

Monitor a different app:

match:
  type: app_call
  app_id: 12345678  # Change to your app ID

Monitor ASA transfers instead:

match:
  type: asset_transfer
  # No app_id needed for asset transfers

Add predicates:

where:
  - "sender in env(ALLOWED_SENDERS)"
  - "amount >= microAlgos(1000000)"  # 1 ALGO

Testing

Test with dry-run:

watch-tower run -c config.yaml --dry-run --once

Finding app IDs

Use AlgoExplorer or the Algorand indexer API to find application IDs:

curl "https://mainnet-idx.algonode.cloud/v2/applications?creator=ADDRESS"